Or you can give a neutral or negative trust rating to the suspects and refuse to remove the rating till they provide proof. Why bother though, people barely read the forum...
That's what I am doing now. I have left some of them negatives (those I managed to discover). Hopefully few users will get alert from it. I know not many cares about it but it's something needs to be taken care of too. By the way, where the hell are you? I do not see you around these days.